http://m.medicalxpress.com/news/2016-02-schizophrenia-expert.html

Mechanically speaking, it’s true. We have nearly no grasp on the mechanics of psychosis; so our ‘diagnostics’ are based on symptom trees that are not exactly sensible. Something is happening, and it involves the brain (and gut/body), but we do not understand the pathologies — despite constant projections in the media that we do.